Hand-tool.



A. J. CROFT.

HAND TOOL.

APPLICATION FILED APR. 1, 1914.

Patented June 16,191 L 5] mm wto'o mum-u mm cm'uruwrw. n. c.

ALFRED a. CROFT, or BROOKLYN, NEW YORK.

HAND-TOOL.

Specification of Letters Patent.

Patented June 16, 1914.

Application filed April 1, 1914. Serial No. 828,651.

To all whom it may concern Be it known that I, ALFRED J. CRor'r, a subject of the King of Great Britain, residing at 35st WVaverly avenue, Brooklyn, Klngs county, New York, have invented a new and useful Improvement in Hand -Tools, of which the following is a specification.

This invention relates to tools for dressing or refinishing the engaging faces of used electrical contact points, such as are employed in the spark control mechanism of a magneto as now constructed.

In the operation of the spark control mechanism of a magneto the engaging faces of the contact points of the breaker, after considerable usage, become pitted or burned and require dressing or re-finishing, and this has heretofore been done by filing, but by this method the faces cannot be given a smooth, unbroken surface, which is essential for perfect operation, and further, to get the best results the faces of the contacts should be at a true right angle to the axis thereof so that a uniform engagement, one with the other, is assured, and this was also practically impossible to attain by the use of a file.

The object of my invention is to produce a hand tool which can be carried in the pocket or in a tool kit, and which is simple of construction and operation, and by which the user is enabled to dress or re-finish the engaging faces of electrical contact points with absolute precision. A further object being to provide a tool of the class described having a receiving chamber wherein the cut tings or chips are deposited and retained, a further object being to provide a rotary cutter and means for partially retarding the movement thereof as it is brought up to the work, which gives the user a more sensitive touch to insure a shallow or light bite into the face of the contact point. A still further obj eot being to provide a tool of the above class, having suitable means for clamping and holding contact points and their supporting members during the operation of dressing or re-finishing.

With these objects in viewtogether with others, which a perusal of this specification will reveal to those skilled in the art, the invention consists in the novel construction and arrangements of parts hereinafter described and delineated in the accompanying drawings-wherein similar reference characters are employed to indicate corresponding parts in the several figures, in which Figure 1, is a central sectional elevation of my improved tool on a greatly enlarged scale and showing a contact point and its supporting arm clamped in position, the out ter being indicated in operative position by dotted lines. Fig. 2, is a side elevation, partly in section, showing the tool at right angles to Fig. 1. Fig. 3, is a horizontal cross section on the line 3-3 of Fig. 2, and Fig. 4c, is a plan view of the cutter.

In the drawings-J have shown at a, a main supporting member having a central chamber 6, and a central tubular extension or bearing 0; a downwardly and inwardly ranging shoulder d, is provided within the chamber and at the top thereof the member a, is provided with external and internal threads as shown, and screwed into the top of the chamber 6 is a cap 0, having apertures f of different sizes to accommodate electrical contact points of different cross sectional dimensions.

A clamp yoke, comprising, in the form of construction shown, a threaded band 9, upright bars 71, and a cross head constituted by a nut i, is screwed onto the top of the supporting member a, and carries a clamp screw j, having a swivcled foot is at the bottom and a knurled head on at the top for operating the screw.

A contact point supporting arm is shown at a, clamped and held so that the platinum contact point 0 projects downwardly through one of the apertures f to be engaged by a cutter p fixed to a shank 7 which has bearing in the extension 0, of the main member a, and is provided at its lower end with a knurled head 8, b which it is operated, as Will be readily un erstood.

Mounted on the shank r, between the head .9 and extension 0, is a spiral spring 25, the top part thereof being housed in a counter bore 0, formed in the lower end of the extension 0. An upward extension at is formed in the chamber Z2, through which the shank r passes,

and this construction provides a uard to keep the cuttings or chips away from the central bore or bearing in the extension 0 and also gives the shank a longer bearing.

The operation of my improved hand tool will be readily understood by those skilled in the art to which it appertains. The work being clamped in position as shown in Fig.

1, after which the cutter is brought up against the action of the spring 27, to engage the work as indicated by dotted lines in the said figure, and after the dressing or re-finishing has been completed th-e'shank is released and the spring t returns the cutter to the normal inoperative position shown in full lines in Fig. 1, in which position the cutter rests on the shoulder cl, and retains or holds captive the valuable cuttings or chips contained in the chamber 6, and which are afterward reclaimed by inverting the tool and forcing the cutter away from the shoulder d, allowing the cuttings or chips to flow out through the apertures f, as will be readily understood,

I therefore reserve the right to all such variations and modifications as properly fall within the scope of the following claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is 1. In a tool of the class described a supporting member having a chamber provided with a shoulder, a removable cap having apertures therein, a cutter movable longitudinally through said chamber and having a shank provided with a knurled head, means for holding the work in position, for retarding the movement of the cutter as it is forced toward the cap to engage the Work, and for operating the cutter over the work for the purpose described.

2. In a hand tool for dressing used electrieal contact points, a supporting member having a central chamber and an extension provided with a central bore, a cap provided with apertures of different sizes and having threaded engagement with the top of the supporting member, a cutter mounted Within the chamber, means for holding the work against the cap so that the part to be dressed projects through one of the apertures and means for operating the cutter to engage the work for the purpose specified.

3. In a hand tool of the class described, a supporting member having a chamber provided with a shoulder and a tubular extension, a rotary cutter operating within the chamber and having a shank passing through said extension and provided with a head, means for holding the work in position and for retarding the cutter as it is moved toward the work for the purpose specified.

4. In a tool of the class described, a supporting member provided with a chamber having a downwardly and inwardly inclined shoulder and a tubular extension, a cutter having a shank passing through the said extension and provided with a head, means for holding the Work in position and means carried by the cutter shank to retard the cutter as it is moved toward the work and for holding the cutter normally against the shoulder for the purpose described.

5. In a tool of the class described, a main supporting member having a chamber provided with an inclined shoulder, and a tubular extension having a counterbore at the end thereof, an apertured cap having threaded engagement with the wall of the chamber, a cutter within the said chamber having a shank provided with a head for operating the cutter, and means for holding the work in position to project through the cap to be acted 011 by the cutter.

In testimony whereof, I, ALFRED J. CnoE'r have signed my name to this specification in the presence of two subscribing witnesses, this 31st day of March 191i.

ALFRED J. CROFT.

lVitnesses:

A. R. APPLEMAN, GEORGE F. BENTLEY.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, I). G. 

